Right off the bat, there are some very worrying issues. For instance, too much focus on psychological differences, but not enough focus on body language and physical appearance (which are known to be huge factors in how we are percieved by other people). These are all issues that self-selection bias produces.

And the part where these differences are used to suggest 'better' behaviors seems to be a surface analysis, without deeper consideration of problems.

For instance, it is suggested that unlucky people should go out and have more experiences. But perhaps it is simply the case that they have tried having new experiences and connecting with people but were overwhelmingly rejected, thus they learned to avoid new experiences. And as to why they were rejected, perhaps they did not know how to approach people or had some other fundamental issue.

For an extreme example of the latter, consider telling an african-american person to 'go out and talk to more people' in Indiana in 1922. This is an extreme example, but cultural/ethnic divisions still very much exist, even in people of the same race, and make it hard for a lot of people to connect and make attempts at connection seem contemptuous.